Flow to Insight: The Visual Feast of Sankey Charts

In the vast landscape of data visualization tools, Sankey diagrams stand out as distinct marvels that can elegantly depict the flow of energy, resources, or materials. Similar to rivers that meander through the landscape, Sankey charts “flow” from source to sink, offering a visual feast for those seeking clarity and understanding in complex systems. This article delves into the creation and applications of Sankey charts, illustrating why they remain an irreplaceable component in the data visualization toolset.

What is a Sankey Chart?

Sankey diagrams, typically used for process flow and resource consumption, take their name from 19th-century engineer and engineer-manager William Playfair. These charts depict complex energy transformations and material flows in a system with minimal space consumption and at a higher degree of legibility than traditional diagram styles. Each Sankey chart is made up of arrows, which follow the “flow path,” and are thickest at the points where there is the largest flow of material or energy.

How to Create a Sankey Chart

Understanding the Basics

To create a Sankey chart, it is essential to understand the flow itself. Identify the start point (source) and end point (sink) of the flow; these should be clearly marked and follow a clear pathway through the entire system. The steps between these points are the “processes” that the Sankey diagram represents.

Choosing the Right Tool or Platform

Several tools and programming libraries can help create Sankey diagrams:

• Microsoft Excel and PowerPoint have basic Sankey diagram features.
• Software suites, such as R and Python with libraries such as gephi, networkx, and visNetwork can be more advanced.
• There are interactive platforms like Sankey Flow (an interactive Sankey editor) and online tools like Plotly for creating interactive Sankey diagrams.

Defining the Data Structure

Sankey diagrams require the data to be structured differently from what’s typical in other diagrams. You need the volume or amount of each flow through each process being depicted with the corresponding rates of each process. Once the data is assembled, define the processes and their order in the workflow.

Designing the Diagram

Start by defining the width of the main channels, or streams, that represent the largest categories within the system. Subsequent processes should be drawn at widths proportional to the amount of flow:

• Identify and create the processes and channels.
• Input the flow data, making sure the volume of the flows matches the diagram’s channels.
• Adjust the angles to prevent crossing paths and maintain a clear, readable diagram.

Applications of Sankey Charts

Sankey diagrams find diverse uses across many fields:

Energy and Environmental Studies

Environmentalists and energy analysts use Sankey diagrams to visualize the energy flow in systems, such as the energy conversion in solar power plants or the carbon footprint of different production processes.

Materials Science

In materials science, engineers and researchers examine how raw materials are transformed into finished products and how resources are used throughout these processes.

Economics

Sankey diagrams are useful for analyzing the financial inflow and outflow within businesses, illustrating the efficiency of economic transactions or the flow of capital across a region.

Urban Planning

Urban designers may develop Sankey diagrams to show the flow of traffic through cities or the utilization of public transportation, providing insights for infrastructure planning and traffic management.

Logistics

Logistics and supply chain professionals use them to map the flow of goods and resources within the supply chain, from raw materials to finished products.

Environmental Reporting

NGOs and government organizations use Sankey diagrams to produce engaging and informative reports on sustainability and environmental protection, offering the public a clearer perspective on complex processes.

Conclusion

The creation of Sankey diagrams might seem complex at first, but they quickly take on a life of their own once the appropriate data and method are applied. When the right tool is used, these diagrams can illuminate the paths of energy, resources, and materials in ways that are almost intuitive. Whether depicting energy flows, economic transactions, environmental impacts, or other complex systems where visualization is key, the Sankey chart stands as an invaluable tool for insight, communication, and decision-making. In a world where data abounds, understanding the flow of that data can lead to actionable knowledge and insights that can transform how we view and interact with our systems.

SankeyMaster

SankeyMaster is your go-to tool for creating complex Sankey charts . Easily enter data and create Sankey charts that accurately reveal intricate data relationships.